Cold interior renovated as standard (9)
'standard' is the definition.
('criterion' can be a synonym of 'standard')
'cold interior renovated' is the wordplay.
'cold' becomes 'c' (eg on taps).
'renovated' indicates anagramming the letters.
'interior' anagrammed gives 'riterion'.
'c'+'riterion'='CRITERION'
'as' acts as a link.
(Other definitions for criterion that I've seen before include "Standard; model" , "Judging standard" , "Standard by which to judge" , "Benchmark - standard" , "London theatre?" .)
But I've got no explanation for this one! Could you help me understand?